Pump housing



A -25,1950 R. RMOCULLOCH EI'AL 2,505,197

PUMP HOUSING Original Filed Dec. 24, 1943 I fl b/ aff md QusizinGudmunclsen Patented Apr. 1950 ,PUMP HOUSING Robert P. Mccuiloch, LosAngeles, and Austin Gudmundsen,

Glendale, CaliL, assignors to Borg-Warner Corporation, Chicago, 111., acorporation of Illinois Original application December 24, 1943, SerialNo. 515,574. Divided and this application April 12, 1949, Serial No.86,912

3 Claims. 1

The present invention relates to fluid displacement apparatus, and ithas particular reference to structures of this character that areemployed for supercharging aircraft engines. The subject matter of thisapplication is a division of the application of Robert P. McCulloch andAustin Gudmundsen, Serial No. 515,574, filed December 24, 1943.

One of the principal objects of the present invention is to simplify theconstruction of fluid displacement apparatus such as superchargers, andto improve the efficiency, operation and dependability of suchapparatus.

An object of the improvements is to materially reduce the weight of theapparatus without affecting the strength of the structural parts ordecreasing the efiiciency of its operation.

Another object resides in providing a fluid displacement apparatuswherein the housing walls are made of a light-weight metal such as analuminum alloy, and the work-faces of said walls, that are proximate tothe rotors, are provided with a liner that is preferably a steel sheetthat is a harder material than the aluminum'alloy, and effects a snugfit with respect to the rotor with which the liner is engaged. The linermay be secured in any suitable manner to the work faces of the housing,and the portions of the rotors that coacttherewith are provided withridges or lands. After assembly of the pump, the rotors are operated ata desirable speed to cute! wear away the contacted surface of the rotor.as a result of this arrangement a minimum clearance is effected betweenthe rotor blades or lobes and the liner work face of the housing.

It is a further object of this invention to provide a liner for the workface of the housing that may be conveniently removed whereby to effectready replacement thereof.

Also it is an object of the present improvements to provide effectivemeans in a supercharger to overcome and prevent a grabbing or "freezing"of the rotors to the work faces when the apparatus is operated ataccelerated or abnormal speed, such as required when the aircraft isflying at high altitudes.

Additional objects, aims and advantages of this invention will beapparent to persons skilled in the art after the construction andoperation of the apparatus is understood from the within description.

It is preferred to accomplish the numerous objects of this invention andto practice the same substantially in the manner hereinafter fullydescribed and as moreparticularly pointed out in the appended claims,reference being made to the accompanying drawings that form a part ofthis specification, wherein:

Fig. 1 is a fragmentary section of a. fluid dis placement apparatusembodying the improvements contemplated herein, the view being on theplane of line Il on Fig. 2;

Fig; 2 is a vertical section taken on the plane of line 22 on Fig. 1;

Fig. 3 is a sectional view on an exaggerated scale showing one of thepreferred forms of this invention and a manner of mounting the linersheet on the housing wall;

Fig. 4 is a view similar to Fig. 3 showing a modified manner of keyingthe liner to the housing wall;

Fig. 5 is a sectional view showing a liner sheet that comprises a metalscreen or mesh; and

Fig. 6 is an exploded view of the structure shown in Fig. 5 and drawn toa larger scale.

The drawings are to be understood as being more or less of a schematiccharacter for the purpose of disclosing typical or preferred forms inwhich the improvements contemplated herein may be made. In thesedrawings like reference characters identify the same parts wherever theyappear in the different views.

The fluid displacement apparatus shown in Figs. 1 and 2 is preferably asupercharger for internal combustion engines, but it will be understoodthat the improvements are adaptable to other types of apparatus. Thehousing comprises the arcuate or semi-cylindrical end walls I 0, aclosure plate I l for the open side of the housing, and a partition orback wall [2 opposite the open side. The top of the housing is providedwith an outlet'stub' I3 intermediate the semi-cylindrical walls l0, andthere is an inlet stub I4 in the bot,- tom of the housing opposite theoutlet stub. Spaced parallel bearing bosses I5 that project from theback wall partition l2 provide journals for the shafts l6 and I! thatare rotatably mounted in said bosses so that their outer ends areprojected beyond said bosses where they have intermeshed timing gears(not shown) secured to them, and one'of said shafts is suitably coupledto a motor or other prime mover that is adapted to actuate the pump.

The rotors, which are preferably of the general shape of the blades of aRoots blower, each comprises a plurality of lobe-shaped members .orblades l8 extending radially from a central hub ID that is anchored toits respective shaft. The outer portions of these blades or lobes [8that are adapted to sweep the arcuate work faces of the aware?semi-cylindrical walls III are preferably provided with parallel landsor ridges 20 vthat are coextensive with the length of each of the bladesand are disposed in spaced relationwith respect to each other at thetips of the blades. The lobes or blades I8 are preferably of hollowconstruction with reinforcing ribs to strengthen them, and the marginaledges of the lobe walls are preferably reduced in thickness bychamfering or under-cutting them as indicated at 2|. This provides arelatively narrow chisel-like shape for these work edges of the lobes orblades.

For the purpose of reducing the weight of the pump, the housing and therotors may be fabricated from a light-weight metal such as an aluminumalloy. This material, however, does not provide a sufliciently hard workface for the housing walls and it is not dependable in maintaining aminimum clearance between the working parts of a supercharger. Toovercome these disadvantages, the work faces of the housing walls areprovided with a liner 22 that comprises a thin sheet of material that isharder than the aluminum alloy of the housing walls. It will beunderstood that the work faces of the housing are the inner surfaces ofthe semi-cylindrical walls ill, the inside surface of the cover plateII, and the surface of the partition or back wall l2, all of whichsurfaces are swept by the rotors during operation of the pump. Thisliner is detachably mounted on the aforesaid surfaces of the housing ina manner that permits its ready removal and replacement wheneverdesired. A variety of types of these liners and attaching means aredisclosed in Figs. 3, 4, 5 and 6.

In Fig. 3 the housing wall, that is hereinafter identified as a, may beany of the housing walls that has a work face adapted to be swept by therotor. The liner 22 is a comparatively thin sheet of hard material suchas steel, and said liner sheet is attached to the housing wall by meansof a layer 25 of a commercial cement known under the trade-name ofCycle-Weld that is manufactured and distributed by Cycleweld Division,Chrysler Motors Company, Detroit, Michigan. This cementitious materialis applied to the surfaces to be united preferably in a plastic'stateand it is allowed to set while the metal sheet 22 is being pressedfirmly against the housing wall.

The inner or exposed surface of the liner sheet 22 may be roughened asshown at 26 in Fig. 3 by blasting the surface with grit. After the partsof the pump are thus assembled, with practically no clearance betweenthe rotors and the liner work faces of the housing walls, the pump isoperated at normal speed which will effect an expansion of the parts dueto the generated heat, and dur ing this initial running of the pump theridges or lands 20 and the undercut edges 2| of the rotor wals will bedressed down and will wear away a portion of the roughened work faces ofthe liners 22, so that the desired minimum clearances are obtainedbetween the respective working parts of the pump.

In the type of assembly shown in Fig. 4, the housing wall a: is providedwith a plurality of channels or grooves 23, and the liner 22 is acomparatively thin sheet of hard metal such as steel. The liner sheet 22is cemented to the housing wall with an intermediate layer 21 interposedbetween them. This intermediate layer is preferably a material such asneoprene or the like that has the soft and flexible characteristics ofrubber and it is applied in a somewhat plastic state. In this instancethe coating of cement 28 is applied to the back of the liner sheet '22and a similar cement coating 29 is also applied to the ridges betweenthe channels or grooves 23 in the housing wall 2:. A suitable cementfor'this purpose is a commercial product manufactured and distributedunder the trade-name "Ty-Ply" by Marbon Corporation of Gary, Indiana,and it is applied in a liquid or semi-liquid state upon the parts to beassembled. When the components of the assemblyare pressed together andheated to cure the neoprene the excess of the neoprene sheet 21 willbulge into the channels or grooves 23 in the housing wall and key theparts together in an effective manner.

In lieu of the metal sheet liner 22 hereinbefore described, the linersheet may comprise a metal screen 30 that is formed by intermeshed orwoven steel strips or steel wires as shown in Figs. 5 and 6. In applyingthis type of mesh or screen liner 30 to the housing wall a: the surfacesof these parts which oppose each other are sprayed with the Ty-Plycement to provide a film 3| thereof on the under surface of the screen30 and a film 32 of this cement upon the surface of the housing wall a:to which the liner is to be united. A ply of neoprene 33 is interposedbetween the thus prepared liner and housing wall and the assembledstructure subjected to heat and pressure to cure the neoprene and unitethe parts. A fiber mat, such as a Masonite board, is placed on the outersurface of the screen prior to the curing operation so that when thepressure is applied the mat will be forced into the interstices of thewire mesh and confine the neoprene back of the outer surface of thisliner sheet. The metal mesh or screen provides a rough outer surfacehaving the characteristics of the grit-blasted surface shown in Fig. 1.This exposed rough surface of the mesh liner 30 may be worn down ordressed in the manner above described with reference to the grit blastedsurface of the sheet metal liner. v

While this invention has been described in detail in its presentpreferred forms or embodiments, it will be apparent to persons skilledin the art, after understanding the improvements contemplated herein,that various changes and modifications may be made therein withoutdeparting from the spirit or scope thereof. It is aimed in the appendedclaims to cover all such changes and modificatLons.

It is claimed:

1. In a fluid displacement apparatus, a housing comprising a pluralityof walls having faces provided with a plurality of channels; a rotor insaid housing; liners on the channeled faces of the housing walls, saidrotor and liners initially engaging with no clearance therebetween, eachliner comprising a sheet that is harder than the material of said rotorand having a grit-blasted abrading work face effective to dress down theengaged surface of the rotor; and an intermediate attaching ply betweensaid walls and liners and comprising a material different therefrom andkeyed into said channels.

2. A supercharger, comprising: a housing including opposed side wallportions and arcuate end wall portions defining a rotor chamber, saidside and end wall portions having surfaces provided with a plurality ofchannels; said housing having a fluid inlet and a fluid outlet portprovided therein, each port communicating with said rotor chamber,liners on the channeled surfaces of said housing walls, each linercomprising a sheet that is harder than the material of said rotor andhaving an inner grit-blasted abrading surface; an intermediate attachingply between said walls and liners and comprising a material differenttherefrom and keyed into said channels; a pair of meshing rotor members,said rotor members and abrading surfaces initially being in frictionalcontact with no clearance therebetween, and said rotors having ahardness less than the hardness of said liner plates, whereby uponinitial rotation of said rotormembers relative to said abradingsurfaces, said rotor members will be automatically dressed down by saidabrading surfaces to provide working clearance.

3. A supercharger, comprising: a housing including opposedside wallportions and arcuate end wall portions defining a rotor chamber; linermeans disposed inwardly of said side and end wall portions,respectively, said liner means comprising metal liner plates providedwith grit: blasted abrading surfaces; means securing said liner platesto said housing including. a ply of hardness of said liner plates,whereby upon initial rotation of said rotor members relative to saidabrading surfaces the outermost peripheral portion and end faces of saidblades will be automatically dressed down by said abrading surfaces toprovide working clearance.

ROBERT P. MCCU'LLOCH. AUSTIN GUDMUNDSEN.

' REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 8 878,480 Green July 16, 19011,158,733 Shepherd et a1. Nov. 2, 1915 1,631,359 Brown June 7, 19271,681,796 Wendell Aug. 21, 1928. 1,686,867 Kuhn Oct. 9, 1928 1,784,866Fahrenwald Dec. 16, 1930 1,785,386 McIntyre Dec. 16, 1930 1,828,409Densmore Oct. 20, 1931 1,837,446 Kauifman Dec. 22, 1931 1,952,179Milkowski et al. Mar. 27, 1934 2,107,260 Ihara Feb. 1, 1938 2,121,068Buechler June 21, 1938 2,167,311 Postma July 25, 1939 2,240,121Patterson Apr. 29, 1941 2,345,975 Herman Apr. 4, 1944 FOREIGN PATENTSNumber Country Date 207,907 Switzerland Apr. '1, 1940 464.475

Great Britain Apr. 16, 1937

